<!DOCTYPE html>
<style>
  table {
    border-collapse: collapse;
  }
  td {
    background-color: rgb(0, 255, 0);
    margin-bottom: 10px;
    height: 100px;
    width:100px;
    border-radius: 50px;
    opacity: 0.5;
  }
</style>
<table>
  <tr>
    <td></td>
  </tr>
</table>
